| 摘要 |
PROBLEM TO BE SOLVED: To provide a heterodyne radio receiver which has a wide intermediate- frequency band and is equipped with a multimode function eliminating the need to mount an IF filter and completely ASIC(application specific integrated circuit)-implemented. SOLUTION: This heterodyne radio receiver has a wide intermediate-frequency band and the output from a 2nd down-conversion mixer 6 of the heterodyne radio receiver is passed through high-pass filters 10 and 11 to select an unnecessary signal and passed through low-pass filters 14 and 15 to select a necessary signal; and the unnecessary signal is up-converted to the intermediate frequency of an up-conversion filter and after the phase is shifted, the signal is inverted in phase and applied to the input of the 2nd down-conversion mixer 6. Consequently, a passing band needed for specific operation can be selected.
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